Filling the wrong fuel in your car - a fatal mistake

Putting the wrong gasoline fuel in a diesel engine can damage the engine, forcing it to be completely replaced.

The common sensory way to distinguish between gasoline and diesel engines for many people is the sound of the engine. Gasoline cars often have a "quieter" explosion than diesel cars. However, with current engine manufacturing technology, diesel cars operating with the Common Rail mechanism (direct injection with high pressure), especially on passenger cars, also have an engine sound similar to gasoline cars.

Some car manufacturers "help" drivers avoid confusion by printing the fuel name on the tank cap. Photo: Caregraf

Misfueling also occurs in some cases when drivers borrow cars from others and do not know what type of fuel to use for the engine. Even the habit of using the word "gas" by many people causes employees at gas stations to refuel cars incorrectly. According to Mr.Nguyen Dinh Hung, lecturer of Traffic Engineering, Department of Automobiles and Electric Power, Ho Chi Minh City University of Technology,The consequences are particularly bad when the wrong gasoline is put into a diesel engine.

Mistakenly put diesel in gasoline engine

This is a low-level hazard. The insoluble nature of gasoline and diesel causes the fuel to often separate into two layers in the tank. Diesel is heavier than gasoline, so it settles to the bottom and enters the combustion chamber first. In a gasoline engine, with pressure and temperature, the mixture of gasoline and air is ignited by the spark plug.

Diesel fuel with high compression ratio, low flash point, difficult or impossible to ignite, generating power when operating in gasoline engines. This leads to the phenomenon of cars "stalling" quickly after filling the wrong fuel. If the driver tries to start the engine, the car will either continue to not start or a lot of black smoke will appear from the exhaust pipe.

Wrong gasoline for diesel engine

Diesel engines operate when the air-fuel mixture is sprayed at high pressure into the combustion chamber. With a high compression ratio, the air-fuel mixture forms a fire center, ignites and generates work. With a low compression ratio and high flash point, the air-fuel mixture self-detonates in the combustion chamber of a diesel engine. Many fire centers are formed, the combustion reaction takes place at many points and creates many fire screens in the combustion chamber.

The resonance factor of many combustion reactions creates pressure that damages the piston head, bends and breaks the connecting rod and crankshaft. If the driver continues to operate the vehicle, ignoring signs such as the vehicle jerking, the "knock" sound at the front of the vehicle, the engine system will be completely damaged.

How to fix

Both cases cause negative consequences to a greater or lesser extent depending on whether the driver continues to operate the vehicle or not. When discovering that the wrong fuel has been put into the car engine, avoid trying to start or force the vehicle to move. Drain all the fuel in the tank, check and flush the engine system such as injectors, combustion chambers, and pistons.

However, the most important thing for car users is to pay attention to filling up with the right fuel at the gas station. Do not leave it to the salesperson or ask someone else to fill it up for you. At the same time, when lending out a car, the owner must clearly state the type of fuel used for the engine.

According to VNE